To carry out the investigation, I am going to use various thicknesses of wires. These will be secured to a ruler

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Introduction

Physics coursework I am going to do an investigation into the resistance of a wire when various currents are passed through it. There are many things that could effect the resistance of the wire we are going to use, these include; Material the wire is made from Temperature of the wire at the time the reading is made The length of the wire The diameter of the wire The material of the wire can affect the resistance because various materials conduct electricity better than others, if the wire were made out of an insulating material such as plastic there would be a very high resistance through the wire. Whereas if the wire were made out of a metal, the electricity would pass through the wire with great ease. Temperature effects the resistance of a wire, this is because if the wire hot when the current is passed through it, the particles will have more energy in them. This means that they will be moving more, and at a greater rate than if they were cold. This means that they will pass the charge on to the next particle easier. Electricity has to move from atom to atom along the wire, which means that if we double the length of the wire, we would need to double the current. ...read more.

Middle

Prediction I predict that the smaller thickness of wires will have a greater resistance than the larger ones, this is because as the thickness of the wire increases, there is a larger amount of space in which the electrical current can travel. Meaning that the atoms will not be as close together as in a smaller wire. The largest thickness of wire will have the smallest resistance. I also predict that as the length of wire increases, the resistance will also increase. The electrical current has to be passed along from atom to atom. If there is a larger amount of atoms present in the wire lengthways, then the current will have to pass through a larger amount of atoms. This means that the resistance of the wire will increase. If the length of the wire is doubled, the resistance across that wire will also double. If the temperature of the wire were to be increased, the resistance would also increased. This is because heat energy causes atoms to vibrate more often, these vibrating atoms disturb the movement of the electrical current therefore a higher temperature would cause an increase in resistance. 0.31 mm Length (cm) 20 40 60 80 100 Voltage 0.38 0.76 1.16 1.6 1.96 Current 0.3 0.3 0.3 0.3 0.3 Resistance 1.27 2.5 3.9 5.3 6.5 Voltage 0.5 1.03 1.51 2.02 2.55 Current 0.4 0.4 ...read more.

Conclusion

This was again due to the amount of atoms the electricity had to pass through before reaching the end of the wire. All three thickness show that the length of the wire affects the resistance. The results also show another part of my prediction to be correct, as the thickness of the wire is decreased, the resistance through it increases. This is because in a thicker wire, the electrical charge is more spread out than in a smaller one, therefore the resistance of that wire will be smaller than a wire where the charge is in a smaller space. If I were to repeat the experiment, there are two things that I would change. I would alter the way in which the length of the wire was measured. By using the crocodile clips to alter the length of the wire used, it was possible for an error to be made. At times the crocodile clips slipped across the wire, meaning that the wire had to be constantly watched to ensure that the correct length of wire was being measured. The second thing that I would change if the experiment was repeated is the thickness of the wires used. I would use more wires, with larger differences between the thickness of them. This will ensure that the results we receive are reliable. Also by using more wires we are making sure that the results we end up with are more representative of the actual experiment. ...read more.

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